TriCo Bancshares Condensed Financial Statements (Parent Only) - Condensed Balance Sheets (Parenthetical) (Detail) - $ / shares	Dec. 31, 2017	Dec. 31, 2016	Aug. 21, 2007
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	22,955,963	22,867,802
Common stock, shares outstanding	22,955,963	22,867,802	15,814,662
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	22,955,963	22,867,802
Common stock, shares outstanding	22,955,963	22,867,802